Lab & Field Testing of AUT Systems for Steel Highway Bridges

FOREWORD

The need for quality control and quality assurance of welds in the fabrication of steel bridge structures has led to the development of a variety of nondestructive inspection techniques. For many years, radiographic testing (RT) has been the preferred nondestructive inspection method used to ensure the quality of butt welds in the fabrication of steel plates for bridge girders. The major advantage of RT has been the capability of producing a radiograph that serves as a permanent record of the inspection. However, the significant health hazards associated with the use of radiographic methods have long been a concern.

Recent advances in computers and ultrasonic technology have led to the development of automated ultrasonic testing (AUT) techniques that produce three-dimensional images of internal conditions in the weld. The AUT image can serve as a permanent record of the inspection and allows for subjective reviews of the inspection findings. Since AUT uses ultrasonic waves, there are minimal health concerns with this method.

This report presents the findings of a study initiated by the Federal Highway Administration's Nondestructive Evaluation Validation Center (NDEVC) to evaluate the effectiveness and viability of automated ultrasonic testing techniques as a replacement for radiographic testing methods for the inspection of butt welds during fabrication of steel plates for bridge girders.

Paul Teng, Director

Office of Infrastructure Research and Development

Notice

This document is disseminated under the sponsorship of the
U.S. Department of Transportation in the interest of information exchange. The
U.S. Government assumes no liability for the use of the information contained in this document.

The
U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers' names appear in this report only because they are considered essential to the objective of the document.

Quality Assurance Statement

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Technical Report Documentation Page

1. Report No.

FHWA HRT-04-124

2. Government Accession No.

3 Recipient's Catalog No.

4. Title and Subtitle

Laboratory and Field Testing of Automated Ultrasonic Testing Systems for Steel Highway Bridges

Fabrication inspection of welds is necessary to ensure the quality of workmanship during the fabrication process. The implementation of automated ultrasonic testing (AUT) methods for inspecting butt welds in steel bridge fabrication is the subject of this report. The primary goal is to evaluate the effectiveness of AUT as a replacement for radiographic testing (RT) for fabrication inspection of welds in steel highway bridges. The AUT results will be compared to RT results. The advantages of implementing AUT as compared to RT for inspecting butt welds in fabrication plants will be addressed.

The study consists of laboratory testing to assess the viability of the AUT system under a controlled laboratory environment and field testing at fabrication plants, during the routine fabrication process, to assess the performance and practicality of the AUT technique and system for use in the fabrication shop environment. AUT, manual ultrasonic testing (UT), and RT systems are employed side by side for fabrication inspection of welds during field testing.